In general, a vehicle wheel alignment assembly is used to ensure that the wheels of a vehicle are substantially parallel to each other, and also perpendicular to the ground. Depending on the vehicle, only the front wheels may be involved in such an operation, or all four of the wheels may be involved.
A variety of different and specific measurements may be checked during an alignment operation. These measurements may include camber and caster angle, and toe-in/toe-out angles, among others. Camber angle refers to the angle of the wheel when viewed from the front of the vehicle. If the wheel has a neutral or zero camber, it will appear to be substantially perpendicular to the ground. If the top of the wheel is leaning out (away from the vehicle), it is considered to have a positive camber. If the top of the wheel is leaning in (toward the vehicle), it is considered to have a negative camber. Too much of a positive or a negative camber can cause excessive wear to the outside or the inside of the tire, respectively.
Caster angle relates to the pivot axis on which the wheels rotate when turned by the steering wheel. Typically, the pivot axis is defined by a line drawn from an upper ball joint to a lower ball joint of the vehicle's suspension system. The caster angle, measured in degrees, is the angle between the pivot axis, projected on a vertical longitudinal plane (side view), and a line perpendicular to the ground.
Toe-in/toe-out involves the parallel relationship between associated wheels (i.e., front wheels or rear wheels) of a vehicle. When the toe-in and toe-out angle is zero, the respective front wheels or rear wheels will be parallel to each other. When the distance between the front portions of a respective pair of wheels is less than that between the rear portions of the wheels, toe-in is said to exist. When the distance between the rear portions of a respective pair of wheels is less than that between the front portions of the wheels, toe-out is said to exist. Too much toe-in can cause rapid wear to both tires.
The wheels of a new vehicle are properly set at the factory. However, typical driving can cause these settings to eventually change, resulting in misalignment. This misalignment can result simply from wear to a vehicle's suspension components, from movement of the suspension components due to rough roads, from damage to the suspension components (e.g., as a result of an accident), or from any combination thereof. Consequently, it is generally necessary that the alignment of a vehicle's wheels be periodically checked and, if necessary, adjusted. Misaligned wheels may cause premature and/or improper vehicle tire wear, and may also adversely affect the handling characteristics of the vehicle.
Therefore, various types of vehicle wheel alignment measurement devices and techniques have been developed over the years. One particular alignment technique involves attaching a vehicle wheel alignment assembly directly to a wheel of a vehicle. More than one such assembly can be used at one time, such that a pair of wheels can be checked simultaneously. These assemblies typically support one or more sensors that are used to check the various wheel settings.
Commonly, these assemblies are clamped to the circumferential flange present on the front of most vehicle wheels. This flange exists at the meeting point between the outer circumference of the wheel and the tire mounted thereto. To this end, different types of vehicle wheel clamping devices have been developed to secure these vehicle wheel alignment assemblies and the associated sensors that are utilized during an alignment procedure. A plurality of such devices are shown in U.S. Pat. No. 6,427,346 to Stieff et al. Similar devices are shown in U.S. Pat. No. 4,815,216 to Swayne and U.S. Pat. No. 4,285,136 to Ragan.
Unfortunately, these prior art devices suffer from various disadvantages that limit their effectiveness when used with certain tire and wheel design alternatives. For example, some modern tire and wheel designs do not always permit access to the outer periphery of the vehicle wheel rim after its assembly to the tire. The Michelin® PAX® System tire and wheel design is an example where the outer periphery of the rim is not exposed.
Certain of the prior art devices mentioned above could potentially be utilized with such a wheel rim style if the clamp fingers thereof were rotated to contact an inner face of the vehicle wheel rim. However, if used in this manner, there is a high likelihood that an inner surface of the wheel rim would be damaged, thus creating an undesirable appearance condition for the vehicle wheel.
Therefore, there exists a need in the art for a vehicle wheel alignment clamping device having clamping members which are useable with a wheel rim design that does not have an exposed outer rim periphery, wherein the clamping members will not damage an appearance face of the vehicle wheel rim, and wherein the clamping members allow the clamping device to be securely attached to the vehicle wheel. The adaptor of the present invention satisfies this need.